In recent years endovascular implantable devices have been developed for treatment of aortic aneurysm. These devices are delivered to the treatment site through the vascular system of the patient rather than by open surgery. The devices include a tubular or cylindrical framework or scaffolding of one or more stents to which is secured a tubular shape of graft material such as woven Dacron, polyester polytetrafluoroethylene or the like. The devices are initially reduced to a small diameter, placed into the leading or proximal end of a catheter delivery system whereafter the delivery system is inserted into the vascular system of the patient such as through a femoral incision. The leading end of the delivery system is maneuvered to the treatment site over a previously positioned guide wire. Through manipulation of a control system that extends to the proximal end of the catheter from the distal end of the system outside the patient the implantable device is then deployed by holding the device at its location and drawing a surrounding sheath. The stent graft or implantable device can then self expand or is expanded through the use of a balloon which is introduced with the stent graft introducible device. The stent graft becomes anchored into position to healthy wall tissue in the aorta such as by barbs whereafter the delivery system is then removed leaving the device in position for reversing an aneurysm in the aorta. All blood flow is channeled through the stent graft so that no blood flow enters the aneurysm thereafter, such that not only does the aneurysm no longer continue to grow and possibly rupture but the aneurysm actually begins to shrink and commonly disappears entirely.
For treatment of thoracic aortic aneurysms in particular it is necessary to introduce the implantable device high up in the aorta and in a region of the aorta which is curved and where there can be strong blood flow.
If an implantable device which is essentially a tube is deployed in the thoracic arch by first releasing the proximal end, that is the end nearer the heart, then blood flow could inflate the stent graft in the manner of a wind sock and there will be considerable pressure of blood flow to displace the implantable device from its intended position.
It is desirable therefore that a deployment device or deployment system is provided which enables release of the distal end of a stent graft or implantable device before the proximal end.
It is the object of this invention to provide a device which will overcome at least some of these problems or at least provide the physician with a useful alternative.